This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Ras is a key regulator of directional sensing during chemotaxis and has been proposed to be a key component of the cell's directional compass. We have demonstrated that the RasGAP (GTPase activation protein) controls the spatiotemporal regulation of Ras activity and the cell's ability to sense the chemoattractant gradient. What is not clear is where NF1 resides in the cell. We propose to use TIRF to localize NF1 in response to chemoattractant stimulation as this will help us model the signaling pathway.